This Dissertation (508 pages) was directed by Professor Margaret Pearson, Department of Government and Politics. The dissertation provides new empirical evidence which shows that environmental activism has been increasing in China since the early 1990s. It explains why participation has increased and why it varies across provinces. It examines the potential emergence of environmental movements and shows the utility of applying social movement theories to studying participation more broadly. Finally, It shows how participation makes a difference in policy outcomes. Both qualitative and quantitative methods, including a statistical analysis of ten years of environmental data, an examination of 125 disputes and over 100 interviews in China, are used to examine the dominant modes of citizen participation; these include direct citizen protests, the dispute resolution and complaint systems, state-mobilized campaigns, and environmental social organizations.